Kunert Norbert, Zailaa Joseph, Herrmann Valentine, Muller-Landau Helene C, Wright S Joseph, Pérez Rolando, McMahon Sean M, Condit Richard C, Hubbell Steven P, Sack Lawren, Davies Stuart J, Anderson-Teixeira Kristina J
Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, 22630, USA.
Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Panama, Republic of Panama.
New Phytol. 2021 Apr;230(2):485-496. doi: 10.1111/nph.17187. Epub 2021 Feb 10.
The effects of climate change on tropical forests will depend on how diverse tropical tree species respond to drought. Current distributions of evergreen and deciduous tree species across local and regional moisture gradients reflect their ability to tolerate drought stress, and might be explained by functional traits. We measured leaf water potential at turgor loss (i.e. 'wilting point'; π ), wood density (WD) and leaf mass per area (LMA) on 50 of the most abundant tree species in central Panama. We then tested their ability to explain distributions of evergreen and deciduous species within a 50 ha plot on Barro Colorado Island and across a 70 km rainfall gradient spanning the Isthmus of Panama. Among evergreen trees, species with lower π were associated with drier habitats, with π explaining 28% and 32% of habitat association on local and regional scales, respectively, greatly exceeding the predictive power of WD and LMA. In contrast, π did not predict habitat associations among deciduous species. Across spatial scales, π is a useful indicator of habitat preference for tropical tree species that retain their leaves during periods of water stress, and holds the potential to predict vegetation responses to climate change.
气候变化对热带森林的影响将取决于热带树种的多样性如何应对干旱。目前常绿和落叶树种在局部和区域湿度梯度上的分布反映了它们耐受干旱胁迫的能力，并且可能由功能性状来解释。我们测量了巴拿马中部50种最常见树种的膨压丧失时的叶水势（即“萎蔫点”；π）、木材密度（WD）和单位面积叶质量（LMA）。然后，我们测试了它们在巴罗科罗拉多岛一个50公顷的地块内以及跨越巴拿马地峡70公里降雨梯度的范围内解释常绿和落叶树种分布的能力。在常绿树种中，π较低的物种与较干燥的栖息地相关，π分别解释了局部和区域尺度上28%和32%的栖息地关联，大大超过了WD和LMA的预测能力。相比之下，π并不能预测落叶树种之间的栖息地关联。在不同空间尺度上，π是水分胁迫期间保留叶片的热带树种栖息地偏好的有用指标，并且有潜力预测植被对气候变化的响应。
